Mixer.



W. H. LARKIN, JE- MIXER.

APPLICATION FILED OCT. 21, 1906.

71.051. Pa fiented Sept. 27, 1910.

witnesses: I Inventor.- m 3%. 72.44.. 3021.4;

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WILLIAM H. LARKIN, JR., OF SOMERVILLE, MASSACHUSETTS, ASSIGNOR T0 UNITEDCONCRETE MACHINERY COMPANY, OF NEW YORK, N. Y., A CORPGRATION OF MAINE.

MIXER.

Specification of Letters Patent.

Patented Sept. 2'7, 1%19.

To all whom it may concern:

Be it known that 1, WILLIAM H. LARKIN, Jr, a citizen of the UnitedStates, and a resident of Somerville, in the county of Middlesex andState of Massachusetts, have invented an Improvement in Mixers, of whichthe following description, in connection with the accompanying drawings,is a specification, like letters on the drawings representing likeparts.

This invention relates to mixers, and more particularly though notexclusively, to apparatus intended for the mixing of concrete or thelike,

In rotary mixers wherein the mixing action is assisted by the relativemovement through the mixer contents of a series of mixing vanes tosecure a thoroughly homogeneous mixture, it is desirable that the vanesshall act to move the ingredients progressively and systematically toand fro through the mixing receptacle, as well as to intermingle thevarious materials which are brought into close association with eachother. For instance, in a concrete mixer, if the bulk of the cement hasbeen thrown in on one side of the drum, it is necessary that that cementnot only be intermingled with the sand and stone in close associationwith it, but that it shall be progressively moved toward the oppositeend of the drum, back again, and so on, during the mixing operation;otherwise the final mixture at one end of the drum would be richer incement than that at the opposite end thereof.

One object of my invention has been to effect this uniform andhomogeneous mixture by a single construction of vanes or blades. This,as well as other objects of my invention, will be best understood byreference to the following description when taken in connection with theaccompanying illustration of one specific embodiment thereof, while itsscope will be more partic ularly pointed out in the appended claims.

In the drawings,Figure 1 shows a development in plan of the cylindricaldrum of a rotary concrete mixer provided with a system of mixing vanesembodying one form of my invention, and Fig. 2 is a perspective of themixing driun shown developed in Fig. 1, the

said drum being partially broken away and having one of 1ts ends removedwith a particular view to showing the relation and construction of themixing vanes. Fig. 3 is a diagrammatic representation of the mixing drumrotatably mounted.

In the drawings I have shown one form of my invention as applied to anordinary type of rotary concrete mixer, such apparatus ordinarilycomprising, as is wellknown to those skilled in the art, a suitablysupported and driven rotatable mixing receptacle, into which theconcrete ingredients are entered and there mixed by the action ofsuitable mixing vanes secured to the interior of the receptacle andmoving with the latter during rotation thereof. In the drawings such areceptacle is presented by the cylindrical drum a having an end closure2'); at each end thereof said closures being provided with axialopenings 0 through which the ingredients are entered or discharged. InFig. 2, for the sake of clearness, but one of the said end closures isindicated, it being understood, however, that a similar closure isemployed at the opposite end of the drum. In practice said drum issuitably supported upon roller bearings and is rotated through gearing,said supports and driven means being herein omitted inasmuch as theyform 110 essential part of the present invention. The mixing vanesemployed are designed especially with a view to obtaining a constantshifting of the materials back and forth lengthwise the drum, as well astheir efiective intermingling, and the principles of the vaneconstruction are well illustrated by those shown in the drawings,although it is to be understood that wide departures therefrom, both asto details and relative arrangement of parts, may be made withoutdeparting from the spirit of the invention. Referring, however, to thespecific details of the illustrated embodiment of my invention, there isprovided a series of V-shapcd vanes (Z, the individual members of whichseries are substantially similar. Each vane comprises a relatively broadportion (Z, the flanged end of which is secured, as by riveting, to theend closure of the mixer, and the flanged bottom riveted to the interiorof the mixer body. This broad vane portion is inclined to a plane takentransversely through the mixer and there fore on rotation of the mixerin the direction of the arrow shown in Fig. 2, tends to slide thematerials engaged thereby down the face of the vane toward the vertex ofthe V-angle, or at the unction of the broad vane with the relativelynarrower vane (F, the latter constituting the opposite side of the V.The vane (Z which, at its junction with the vane (Z, is approximatelyhalf the width of the latter, extends to the opposite end of the drum onan inclination reverse from that of the broad vane (Z and, terminates ina gradually broadened face d which is flanged and riveted to theadjacent end closure of the mixer, the vane at its bottom being fixedlysecured to the body of the mixer drum by flanged portions rivetedthereto. The unctions of the several sets of V-shaped vanes, preferablybut not necessarily, lie in a trans verse plane at one side of thecentral transverse plane of the mixer, the vanes (Z having the sameinclination as the vanes (Z and longer than the latter. As the drumrotates and the vanes ascend, the materials are caused to slide down theface of both vanes toward the unction, but the bulk of the materialsupon the bottom of the mixer is caused to move in the general directionof the length of the longer vanes (Z At the same time some of thematerials slide over the edge of the vanes and into the compartmentformed between the same and the next adjacent vanes, the amount of suchmaterial passing over the edges of the vanes increasing as the latterascend. Finally, the last remnants of the materials elevated by thevanes will be discharged from the vertex. The general effect of thesevanes, however, is to produce a plurality of streams of materialsflowing down and across the body of the drum in the direction of theelongated vane.

In order to produce counter-flow of material the vane d, which extendsabove the other vane at the junction therewith, has an extension (Zbeyond the junction and above the bottom or body of the mixer, the saidextension being of a width which is the difference between the width ofthe broad vane and the narrow vane, that is, approximately half thewidth of the broad vane and extending to the narrower side of the nextadjacent V-shaped vane, to which its end is secured in any suitable way,as by the strap (Z As the vanes ascend much of the material which liesagainst the broad vane cl, Whether such material is carried thereto bysliding along the vane (Z or is dropped on to the said vane from thepreceding vanes, will be slid along the vane extension (Z over and abovethe material moving transversely thereto in the next adjacentcompartment and delivered in part against the opposing face of the nextadjacent oppositely inclined narrower vane, but in greater part againstthe broadened face (Z of the second adjacent narrower vane and close tothat end of the mixer. There is thus produced a flow of material havinga general direction from one end of the mixer toward the opposite endthereof lengthwise the longer and narrower vane and a counter-flowtoward the opposite end of the mixer in the general direction of thebroad faced vane, the former flow being along or adjacent the body ofthe mixer and the latter over and above the same. This is what I havefound oc curs in practice and, in fact, during normal operation of amixer constructed according to the illustrated embodiment of myinvention there are produced three or more streams of materials flowingdown and obliquely across the mixer body in one direction, and three ormore streams flowing transversely the same in an oppositely inclineddirection.

The broadened face (Z of the mixer vane (Z fulfils a double function inthat it prevents the materials which are thrown toward it by the actionof the vane extensions (Z from escaping from the drum through theopening 0 and also presents in effect a baffle plate to the materialscausing the sand and cement which are thrown vigorously thereagainst tobe ground together and more effectively intermingled by their veryimpact against its face.

This mixer is found to be very effective in combining the shovelingaction which results from elevating material and then dropping it, thecompound shifting action which results from giving the materials theseveral progressive movements described, and the mixing action whichresults from the violent meeting of the ingredients with each other andwith the various vanes.

lVhen the materials have been sufliciently mixed they are withdrawn fromthe mixer in the usual way by inserting an inclined chute into the openend of the mixer and allowing the material carried up by the vanes to bedropped on to the same, all of which is Well understood by thosefamiliar with the art.

It is to be understood that my invention is not limited to the detailsor dimensions of the blades Which forillustrativepurposes have beendescribed or to the construction or rela tive arrangement of parts or tothe application thereof to a mixer of the type or construction shown,but that my invention may be applied to other forms of mixers withoutdeparting from the spirit thereof.

The term drum is used generically with reference to any form of mixingreceptacle and without reference to its geometrical shape.

Claim:

1. A concrete mixer having a rotatable mixing drum and a series ofV-shaped mixing vanes therein, each vane having one side of the V higherthan the other at the apex and the other side having a vane extension inline therewith beyond the apex and lying above the peripheral wall ofthe mixer.

2. A concrete mixer having a rotatable mixing drum, a series of V-shapedmixing vanes therein, one side of the V being higher than the other atthe apex and having a vane extension beyond the apex above the bottom ofthe mixer and extending and secured to the narrower side of the next adjacent set of V-shaped vanes.

3. A concrete mixer having a rotatable mixing receptacle and mixingmeans secured to the interior thereof to rotate therewith, said meanscomprising pairs of angularly inclined vanes joined at an angle, onemember of each pair being broader than the other at its junctiontherewith and extending to substantially one end of the mixingreceptacle, and the other, narrower member of the pair extending fromthe junction to substantially the opposite end of the mixing receptaclebut terminating in a relatively broader end portion.

i. A concrete mixer comprising a rotatable mixing drum having an axialend opening, mixing vanes secured to the interior of the body of saidreceptacle and inclined to cause travel of the ingredients contactingtherewith toward one end of said receptacle, other vanes inclinedtransversely of said first mentioned vanes and having each a broadenedface opposed to the said vanes near the end opening to prevent escape ofthe material deflected by said first vanes through said opening.

5. In a rotary concrete mixer, the combination with pairs of annularlyinclined mixing vanes, of other vanes each forming an extension of onemember of each of said pairs and passing between adjacent pairs butraised above the peripheral wall of the mixer to permit the flow ofmaterial beneath the same and serving as bafiie plates for the materialsmoving from one pair of vanes to the next, thereby assisting in themixing.

6. A rotary concrete mixer having pairs of V shaped vanes. each pairextending from one end to the other of the mixer, and bai'lie plateseach forming an extension of one of each of said pairs of vanes andconnecting these with a vane of an adjacent pair for conveying materialfrom the compartment formed by the former pair to the compartment formedby the latter pair.

7. A concrete mixer having a cylindrical, rotatable drum provided withan axial end opening for the entrance or discharge of materials, mixingmeans within said drum comprising pairs of V-shaped mixing vanes fixedlysecured to the drum to rotate therewith, each pair comprising arelatively broad vane inclined to the axis of the mixer and extendingfrom one end of the mixer to the junction of said vane with theremaining one of the pair, the said remaining one being narrower thansaid first vane at its junction therewith and extending to the oppositeend of the mixer on a reverse inclination, a vane extending from thejunction of said two vanes to the narrower one of the next adjacentpair, said V-shaped vanes being secured to the bottom of the mixer, andsaid extension being separated from said bottom, and the second memberof said V- shaped extension being provided with a broadened face lyingin the path of the material moved by the preceding vane extension.

In testimony whereof, I have signed my name to this specification, inthe presence of two subscribing witnesses.

WILLIAM H. LARKIN, JR.

Witnesses THOMAS B. Boo'rrr, FRANKLIN E. Low.

